program ex(f1,f2);
 type
  zn=array [0..50000] of longint;
  la=array [0..10] of longint;
 var
  a:zn; c,d:la; f1,f2:text;
  i,j,k,m,n,l,s,p,min:longint;
 begin
  assign(f1,'busses.in'); reset(f1);
  assign(f2,'busses.out'); rewrite(f2);
  for i:=1 to 10 do read(f1,d[i]);
  readln(f1);
  readln(f1,n);
  a[1]:=d[1];
  if 2*a[1]>d[2] then a[2]:=d[2] else a[2]:=2*a[1];
  for i:=3 to 10 do
   begin
    min:=d[i];
    for j:=1 to (i div 2) do
    if a[j]+a[i-j]<min then min:=a[j]+a[i-j];
    a[i]:=min;
   end;
  if n>10 then
   for i:=11 to n do
    begin
     min:=99999999;
     for j:=1 to (i div 2) do
     if a[j]+a[i-j]<min then min:=a[j]+a[i-j];
     a[i]:=min;
    end;
  writeln(f2,a[n]);
  close(f1);
  close(f2);
 end.